i7 860 + biostar t5xe, ddr 1333, 600w power supply all new, with gtx260. my computer is fine, except when i start gaming it shuts down immediately. why is that? i asked my friend, he suggested something is wrong with the voltages in the bios, its all stock. i haven't messed with any of that, would like to get second opinions. thanks!!
Load them up and watch for spikes when you start gaming. Some of these will let you log temps to a file.
The next time your PC shuts down, wait a couple minutes then turn it back on. Open the Event Viewer (I'm assuming your running Windows) and look in the Application and System windows logs for any errors or warnings that occurred at/near the time of shutdown.
If the shutdown took a moment or so, I'd consider overheating first. Since you say it is immediate, I'm more inclined to suspect an overloaded PSU, that cannot handle the load when your GPU starts sucking down power for 3D gaming. What brand and model is it?